1. Field of the Invention
The present invention relates to sabots for gun-launched projectiles and, more particularly, pertains to sabots having a solid propellant-carrying means for increasing the muzzle velocity of saboted projectiles.
2. Description of the Prior Art
In the field of ballistics, the sabot has found widespread use as a means of improving projectile velocity, accuracy and range. These improvements are possible in sabot-supported projectiles because the bore area on which the gun pressure acts is generally increased with only a relatively small increase in total projectile weight.
It has been long recognized that one of the most mass-efficient sabots presently used to launch kinetic energy projectiles from high performance guns are those constructed using the double-ramp principle. For practical reasons related to the initial centering of the projectile in the bore of the gun and the need to provide aerodynamic lift during discard, the most successful designs utilize a forward scoop. Such designs have been fully developed for use in the 25 mm chain gun used in the M2/M3 Bradley vehicle and in the 120 mm tank gun used in the M1A1 tank. Examples of sabots employing a forward scoop may be found in U.S. Pat. Nos. 4,284,008 and 4,372,213. Older, less efficient "saddle" designs, referred to in detail in these patents, also use a forward scoop. All of these designs have a common feature, an empty space or cavity between the rear of the forward-located scoop and the front of a bulkhead assemblage that contains the seat for the projectile obturator. When loaded in the bore of a gun, such space is bounded in the radial direction by the exterior of the sabot and the gun bore.
Attempts, utilizing liquid propellants, have been made to use this space to contain a traveling charge. These attempts, motivated by the hope of increasing the muzzle velocity of the projectile through ignition of this traveling charge, have, thus far, met with serious problems. One problem of major concern is the proper ignition of the liquid propellant. Proper functioning to attain the traveling charge effect involves pressurization of the space or cavity to eject the liquid out of the cavity into the space behind the projectile for combustion. This necessitates the introduction of high pressure gas channels to transport propellant gas from the rear of the sabot to the most forward portion of the cavity to force the liquid propellant from it, but without igniting it. Malfunctions related to the failure to maintain projectile integrity, probably caused by the forward ignition of the liquid propellant, have occurred.
Others have attempted to affix solid propellants to the rear taper of a sabot to generate a traveling charge, but difficulties in attaching the propellant to the sabot have occurred. In any event, such a device occupies space currently used for part of a conventional charge.
Consequently, those concerned with the development of sabot-supported projectiles have recognized the need for a means that effectively utilizes the existing space in mass-efficient sabots to store gun propellant. The use of such space for gun propellant will increase the amount of propellant available for propulsion thereby increasing the muzzle velocity of the saboted projectile. The present invention fulfills this need.